Notice of Weekly Natural Gas Storage Report Changes

The U.S. Energy Information Administration (EIA) is announcing changes to the format of its Weekly Natural Gas Storage Report (WNGSR) to better serve its customers who make use of automated computer systems to collate information on changes in natural gas storage.

Specifically, EIA intends to enhance the WNGSR summary table. In addition to what is currently presented, EIA plans to provide an estimate of the "implied flow" of working natural gas into or out of underground natural gas storage facilities that excludes reportable reclassifications-those totaling 7 billion cubic feet (Bcf) or more-from the weekly "net change" in working natural gas. The "implied flow" would represent flow activity into or out of underground storage facilities derived from comparing the working gas stocks-excluding reportable reclassifications-reported by storage operators to EIA for the two most recent weeks on the Form EIA-912, Weekly Natural Gas Storage Report.

The proposed new summary table estimate of "implied flow" excluding reportable reclassifications will allow users interested in that value to find it directly, rather than having to calculate it using the data on working gas storage levels in the prior and current week in conjunction with data on reclassifications that were described in a note below the table. For example, the WNGSR for the week ending August 2, 2013, reported a national net change in working natural gas storage inventories that included a 14 Bcf reclassification of base natural gas to working natural gas. The report was made in compliance with EIA's long-standing methodology, published on November 25, 2008, that was based on extensive feedback from Federal Register Notices dated November 12, 2002, and April 26, 2005. The effects of the reclassifications were described in a note below the table.

As in past situations where it has changed the format of a time-sensitive data release, EIA will provide further notice of technical details, a schedule for the change, and a test site where users may test their automated data retrieval systems on dummy data before the new format goes "live." Additional information is provided in the Background section below.

Until the format change outlined above is introduced, EIA will disclose any reportable reclassifications in notes below the WNGSR summary table, but exclude them from the summary table with the current report week's working natural gas stocks and "net change" estimates.

Background

The WNGSR presents estimates of the volume of working natural gas in underground storage as of the previous Friday along with the volume in storage one week earlier, and the week-over-week difference as a "net change" in working natural gas. Typically, changes in working natural gas levels result from flows of natural gas into or out of storage facilities. However, inventory adjustments such as reclassifications and data revisions can result in changes to inventory levels unrelated to these flows. Under EIA's published methodology, reclassifications and revisions can both affect inventory levels, but in different ways:

Reclassifications occur when operators change the classification of natural gas in a storage field between base natural gas and working natural gas, owing to accounting, engineering, infrastructure, or ownership changes. EIA reports reclassifications in the WNGSR when the net effect of the reported changes totals at least 7 Bcf on a regional or a national level. Under the terms of its published policies, EIA applies the change for reportable reclassifications in the week it is verified, resulting in its inclusion in the reported "net change" described above.

Revisions refer to corrections reported by respondents affecting previously submitted data. EIA reports revisions to previously published data in the WNGSR when the net effect of the reported changes is at least 7 Bcf on a regional or a national level. Consequently, published revisions do not affect the "net change" reported on the WNGSR, because the "net change" is calculated as the difference between the current week's data and the revised value from the preceding week.

Upcoming Changes to the WNGSR

EIA will add an estimate of the "implied flow" of working natural gas into or out of storage facilities that will exclude the effect of reportable reclassifications from the "net change" in working natural gas to the WNGSR summary table. EIA will continue to provide an explanatory note separating the effect of reportable reclassifications from the implied flow included in the "net change." Separating the "implied flow" from the "net change" explicitly in the table will permit automated retrieval systems to choose the measure most directly relevant to their purpose: either the "implied flow" if they are attempting to understand the week's physical flow of natural gas into or out of storage facilities, or "net change" if they want to include the effects of reportable reclassifications.

For example, using this new table format, the WNGSR for the week ending August 2, 2013, would have included an "implied flow" totaling 82 Bcf in addition to a "net change" of 96 Bcf in order to distinguish the 14-Bcf reclassification that was reported for the week (see mock-up table). The "implied flow" excludes only the effects of reportable reclassifications from the "net change" in working natural gas levels. The "implied flow" may contain the effects of unpublished net revisions to working natural gas levels of less than 7 Bcf. The new report format is entirely consistent with the established estimation methodology and the revision policy.

EIA will implement publication of these modifications to the WNGSR table after a period of public testing. The testing period will be preceded by a public announcement later this year. The transition to the newly formatted reports should be seamless for all customers. However, customers using automated retrieval systems will have opportunities to test the new reports, and to modify their automated systems as necessary, during the testing period. Details of the testing, including test files, instructions, and the schedule, will be provided when the testing is announced. The implementation date for these changes will be announced after the public testing is completed.

Interested report users are encouraged to sign up for the "Natural Gas Underground Storage" email list to ensure timely updates of the planned changes and notification of any future changes.

In the interim, EIA will modify its treatment of reportable reclassifications that net to at least 7 Bcf if they occur prior to the rollout of the new WNGSR table format. Reportable reclassifications to working natural gas stocks will not be included in current inventory levels published in the table until the following report week. Instead, EIA will include a note below the table documenting the reportable reclassification, and these volumes will be included in the table in following week's report. As a result, EIA will not include the effects of reportable reclassifications to working natural gas stocks in the "net change" reported in the table.